Cephalexin dosage, forms, and strengths

Medically reviewed by Karen Berger, Pharm.D.

Licensed Pharmacist

Updated Aug 28, 2025 • Published Aug 3, 2021

Datos Verificados

In this article:

Forms and strengths
Adult dosage
Adult dosage chart
Child dosage
Child dosage chart
Pet dosage
Usage instructions
FAQs

In this article

Key takeaways

Cephalexin is a generic antibiotic in the cephalosporin drug class. It may be prescribed to treat certain types of bacterial infections, such as strep throat, urinary tract infections, and skin infections. However, like all antibiotics, it does not treat viral infections.
Your healthcare provider will prescribe the dosage and duration that is appropriate for your infection, taking into account individual factors such as the severity of your symptoms, medical history, or any other medical conditions you have.
Always finish the full course of antibiotics. Even if you start to feel better, stopping the medicine too early could result in the infection returning and contribute to antibiotic resistance.

Cephalexin is an antibiotic (also known as antimicrobial) that is FDA-approved to treat bacterial respiratory tract infections, ear infections, bone infections, skin infections, and genitourinary tract infections. Cephalexin is a generic drug that is part of a class of medicines called cephalosporin antibiotics. It works by preventing bacteria from making cell walls, causing the bacteria to die.

Related: Learn more about cephalexin

Cephalexin dosage, forms, and strengths

The chart below shows some common uses for cephalexin, along with standard dosages. These are general guidelines. The duration of treatment is generally 7 to 14 days. However, individual factors such as type and severity of infection, as well as kidney function, are taken into consideration when the healthcare provider determines the appropriate dosage and duration of treatment.

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Cephalexin dosage chart for adults
Indication	Standard dosage*
Bacterial infections	500 mg by mouth every 12 hours or 250 mg by mouth every 6 hours
Strep throat	500 mg by mouth every 12 hours or 250 mg by mouth every 6 hours
Uncomplicated urinary tract infection	500 mg by mouth every 12 hours or 250 mg by mouth every 6 hours
Bacterial skin or skin structure infection	500 mg by mouth every 12 hours or 250 mg by mouth every 6 hours

* Dosage and duration may vary by type and severity of infection; the duration of treatment is generally 7 to 14 days.

Cephalexin is available in the following dosage forms:

Capsules: 250 mg, 500 mg, 750 mg
Tablets: 250 mg, 500 mg
Oral suspension: 125 mg/5 mL, 250 mg/5 mL

Cephalexin dosage for adults

Cephalexin is typically taken as a capsule by mouth two, three, or four times daily, with or without food. It should only be used for bacterial infections. Antibiotics such as cephalexin cannot treat viral infections like the common cold, flu, or COVID-19. Cephalexin dosing depends on the type of infection it is treating.

Cephalexin dosage for adults:

Bacterial infections (varies by type and severity of infection): 500 mg by mouth every 12 hours or 250 mg by mouth every 6 hours
Streptococcal pharyngitis (strep throat): 500 mg by mouth every 12 hours or

250 mg by mouth every 6 hours

Uncomplicated urinary tract infection: 500 mg by mouth every 12 hours or 250 mg by mouth every 6 hours
Bacterial skin or skin structure infection: 500 mg by mouth every 12 hours or 250 mg by mouth every 6 hours

Maximum cephalexin dosage for adults:

The maximum adult dosage is 4000 mg per 24 hours (in two to four equally divided doses). However, older adults or people with kidney disease may have a lower maximum dosage.

Cephalexin dosage for children

The following chart provides information about cephalexin dosage by age and indication. For more information, consult your child’s healthcare provider.

Cephalexin dosage by age
Indication	Age	Standard dosage	Maximum dosage
Middle ear infection (otitis media)	Children (1 year and older) and adolescents	75 to 100 mg/kg/day by mouth divided into 3 or 4 doses	2000 or 4000 mg in 24 hours
Strep throat	>1 month old	25 to 50 mg/kg/dose by mouth every 12 hours	500 mg per dose
Bacterial community-acquired pneumonia	Children (1 year and older) and adolescents	75 to 100 mg/kg/day by mouth divided every 6 to 8 hours	4000 mg per day
Uncomplicated urinary tract infection	1 year to 2 years old	50 to 100 mg/kg/day by mouth divided every 6 hours	Not specified
Uncomplicated urinary tract infection	3 years to 17 years old	25 to 50 mg/kg/day by mouth in 2 to 4 divided doses, or for severe infections, 50 to 100 mg/kg/day by mouth in 3 to 4 divided doses	2000 mg per day (4000 mg per day if using dosage for severe infections)
Bacterial skin or skin structure infections	Children (1 year and older) and adolescents	25 to 50 mg/kg/day by mouth divided every 6 or 12 hours	2000 mg per day for most skin or skin structure infections; 1000 mg per day for impetigo

Cephalexin dosage for adults and children over 15 years old with kidney impairment

People with impaired renal function may need a dosage adjustment based on creatinine clearance (CrCl).

CrCl ≥ 60 mL/min: No adjustment required
CrCl 30 to 59 mL/min: No adjustment required, but the maximum daily dosage should be 1 gram or less
CrCl 15 to 29 mL/min: 250 mg every 8 hours or 250 mg every 12 hours
CrCl 5 to 14 mL/min (not on dialysis): 250 mg every 24 hours
CrCl 1 to 4 mL/min (not on dialysis): 250 mg every 48 hours or every 60 hours
There is not enough data to make dosage adjustments for people who are on hemodialysis.

Cephalexin dosage for adults aged 65 years and older

Cephalexin is excreted by the kidneys. People with impaired renal function are at a higher risk of reaction to cephalexin. Also, some drugs in the cephalosporin drug class have been associated with causing seizures, especially in people with kidney problems who took the full dose. Because older adults are more likely to have impaired kidney function, the manufacturer recommends that “care should be taken in dose selection.”

Cephalexin dosage for bacterial infections

Adults: 500 mg by mouth every 12 hours or 250 mg by mouth every 6 hours (varies by type and severity of infection)

Pediatric patients: 25 to 50 mg/kg/day by mouth divided every 6 to 12 hours (varies by type and severity of infection)